Field of the Invention (Technical Field)
The present invention relates to a railway comprising rails that are at least in part at regular places along their longitudinal direction supported by and mounted on supporting pads or baseplates, wherein each baseplate is fixed to a sleeper resting on ballast, and wherein each rail is clamped to the baseplate with a clamping plate that is fitted to the baseplate with a clamping bolt, and which clamping plate has opposite extremities of which a first extremity rests on a cam provided on the baseplate and a second extremity rests on and presses the rail to the baseplate.
Description of Related Art
EP-A-2 339 068 addresses the known problem of existing railways that the support of neighboring or adjacent railway parts may vary depending on the deterioration of the ballast, particularly although not exclusively shortly after establishing a new railway. The problem is also existent with older railways, and is connected with the deterioration of the supporting structure of the sleepers which may be different for the first railway part and an adjacent second railway part. The problem is particularly prominent when the first railway part rests on ballast, and the second adjacent railway part rests on a more fixed structure such as concrete, as may be the case at a railway crossing. Over time the ballast may become more dense, and this deterioration is promoted by the regularly passing trains, which in turn will result in accelerated densification of the ballast. The ballast getting more dense may even eventually result in that the sleepers will no longer be supported by ballast, but will be hanging from the rail. This is very detrimental to passenger comfort, and may result even in rail failure.
EP-A-2 339 066 addresses these problems by applying two replaceable filler parts that are placed on top of each other that together exhibit a thickness in the vertical direction that matches and fills the room or space between the rail and the sleeper so as to cause that the rail is maintained at a pre-established level. Accordingly in EP-A-2 339 066 the room or space between the rail and the baseplate is selectable at a predefined measure corresponding to a selectable height of the rail between a first lowest position of the rail and a second highest position of the rail, wherein in the lowest position of the rail the first extremity of the clamping plate resting on the cam is above the second extremity of the clamping plate resting on the rail, and wherein in the highest position of the rail the first extremity of the clamping plate resting on the cam is below the second extremity of the clamping plate resting on the rail so as to arrange that with variation of the height of the rail the clamping plate rotates having its center of rotation on top of the cam. The clamping plate thus makes an angular movement.
A first and a second of the two replaceable filler parts are each embodied as wedges sloping in the longitudinal direction of the rail and have matching oblique contacting surfaces, whereby in use the oblique surfaces of the first wedge and the second wedge rest on each other so as to cause that opposed surfaces of the first wedge and the second wedge that contact the rail and the sleeper, respectively are substantially horizontal. Further the wedges have in the longitudinal direction of their oblique contacting surface regularly distributed depressions transverse to the longitudinal direction of the rail so as to arrange that in said longitudinal direction the oblique contacting surface of each wedge is shaped as a series of connected sloping surface-parts. This makes it easy to adjust for the dimensions of the room or space between the rail and the sleeper, also when these dimensions do not exactly match the available thickness groups of the filler parts, whilst the cooperating depressions on the contacting surfaces of the abutting wedges provide security against longitudinal movement of these wedges which might otherwise cause that the support of the rails by the ballast is lost. Another benefit of the solution disclosed in EP-A-2 339 066 is that it is easily possible to adjust to the room or space—also afterwards—that possibly develops over time between the rail and the sleeper, whilst the sleeper can remain supported by the underlying structure, notably the ballast.
A problem that may exist that is due to the load exerted by passing trains is that the parts of the railway are subjected to repeated deformation. These deformations result in small but repeated movements of the parts of the railway with respect to each other. In the known railway the baseplate may then repeatedly frictionally engage the guide or guides that keep it in place, which is to be avoided.
Another problem is that the repeated deformation of the railway may cause that the filler parts, particularly the lowest filler part that rests on the baseplate moves out of position.
Still another problem is that the application of the filler parts to ensure that the rail is maintained on the required height, may result in track gauge narrowing with increasing height of the rails.